In a micro wave band and a millimeter wave band, a waveguide which is a low-loss transmission path is widely used as an input and output interface with a transmission and reception antenna. For example, Patent Literature 1 explained below discloses a technique of a structure for realizing a lower-loss, wider bandwidth, and smaller high frequency circuit device used for a mobile wireless terminal, a video transmission, and the like for a submillimeter wave band and above.
In the technique disclosed in Patent Literature 1, a semiconductor for forming a high frequency circuit, a transmission path of a dielectric substrate, a metal electrode, and a ground metal electrode are provided in a ground metal housing, and a high frequency signal is retrieved to a waveguide through a rectangular hole having the same size as a wave guide provided in the metal housing.